This invention relates generally to vertically oriented wind driven assemblies, more particularly to vertically oriented, wind driven assemblies which are rotational speed controlled by relating the exposure of wind capturing elements according to the rotational speed of the assembly.
Commonly called windmill or wind impeller, a wind driven assembly converts wind force into a mode of force for various applications. A wind driven assembly includes generally a rotor or shaft, wind capturing elements attached thereto, and a means to transfer the rotational action of the shaft. Typically, a wind driven assembly is coupled either mechanically or electrically (through an electrical generator means) to various energy consumers such as water pumps, lighting, heating, refrigeration, storage batteries, and the like. An assembly coupled to a means to produce electricity or an electrical generator is called a wind driven electrical generator. Electrical generators are particularly efficient within a narrow range of rotational speeds (RPM) so that whenever the RPM is less than or exceeds this range of RPM, the efficiency of the electrical generator decreases. Therefore, it is of advantage to rotate an electrical generator within this range of RPM independently of the electrical load placed upon the generator. There are other energy consumers which have their maximum energy conversion relating to a constant rotational speed range of the wind driven assembly.
Because wind velocities vary in both speed and direction, it is advantageous to have an assembly which maximizes the usefulness of the wind energy over a variety of wind conditions. When coupled to an electrical generator, it is advantageous to control the speed of the wind driven assembly so that the RPM of the wind driven assembly matches the efficiency range of the coupled electrical generator independently of the load on the generator.
The wind's variability covers a wide range of speeds, from still or generally zero wind speed to gusts and gales over 100 miles per hour. The forces upon a wind impelled assembly vary with the square of the speed of the wind and the power, that is the rate at which wind can be made to do work varies with the cube of velocity. An important consideration is effect of wind speed upon the wind driven assembly itself, the assembly should be protected from gales and gusts while adapting to variable wind conditions. A substantially cylindrical shape offers a smooth or neutral rotational exposure to the wind; that is, a vertically oriented cylindrical element mounted axially should not rotate in either direction irrespective of wind speed.
A particular advantage of a vertically oriented wind driven assembly is that it operates independently of wind direction and responds to wind speed only. Additionally, it is advantageous to have the wind capturing elements at increased or maximum exposure to the forces of the wind at low wind velocities and minimum, nearly neutral, exposure to the wind at higher wind velocities.
There are various strategies described in the prior art to control the rotational speed of a wind driven assembly: Brulle, U.S. Pat. No. 4,410,806, describes a vertical axis windmill having articulated vertical blades, the profile and orientation of the blades being adjustable for a constant rotational velocity by a microprocessor controlled actuator. Peed, U.S. Pat. No. 4,061,926, teaches a vertical axis windmill having a pair of oppositely rotating co-axial turbines, the speed of the turbines controlled by small, peripherally located, concave air scoops. The air scoops retract from the wind according to centrifugal forces acting upon masses linked to the scoops, or extend into the wind according to springs, the spring balanced against the centrifugal forces on the masses. Magoveny et al., U.S. Pat. No. 4,047,834 discloses air scoops peripherally attached to an inner rotor, the profile of the air scoops changing according to wind currents passing between funnel-shaped passages.
These devices either fail to offer a smooth or nearly neutral configuration to the wind under extreme wind conditions and are very complex in design.
There exist a particular need for means to recharge electrical storage batteries on sailing vessels. Sailboats often use appliances which depend upon electricity for their power viz., navigational equipment, lights, radios, starters for auxiliary engines and the like. Most sailboats now use small, gasoline powered electrical generators to periodically recharge their batteries, or periodically run auxiliary engines coupled to electrical generators to recharge their batteries. The systems require periodic monitoring of the storage batteries to determine when the batteries should be recharged.
Typical gasoline powered recharging operations are noisy, and running an auxiliary engine for the sole purpose of recharging storage batteries causes excessive wear on the engines. To avoid these problems, some boats have employed solar charging grids which convert solar energy directly into electrical energy, typically for trickle generators. There also exists small wind impelled electrical generators for electrical power production which are not speed governing. These systems are mounted at or near the bottom of a mast or set upon a boat deck where they can be quickly removed during periods of very high winds. The wind speed at the deck level is low and variable compared to the wind speed which exists about and above the sail area. It can be appreciated that these wind generators must be removed during periods of high wind or when the activity aboard the vessels are impeded by these generators.
Accordingly, one object of the present invention is to provide a new and improved vertically oriented wind driven assembly.
Another object is to provide for a new and improved self-governing vertically oriented wind driven assembly with a mass impelled governing system linking mass means to a lever system controlling semicylindrical shaped wind scoops.
Still another object is to provide a self regulating vertically oriented wind driven assembly having scoops which extend and retract according to rotational velocity, thereby maintaining a useful rotational speed of the assembly.
Another object is to provide a self-governing vertically oriented wind driven assembly that adapts to various wind speeds by controlling the position of wind scoops, movable from an open, fully exposed position for low wind speeds, to a closed position, forming a substantially neutral profile configuration for high wind speeds. Another object of the present invention is to provide a self-governing vertically oriented wind driven assembly wherein the rotational speed of the assembly is fairly constant independently of wind velocity and load upon the energy consuming means.
An additional object of the present invention is to provide a new and improved vertically oriented wind driven assembly which offers a smooth or nearly neutral exposure to the wind under extremely high wind velocities.
A still further object of this invention is to provide for a lightweight, self speed regulating, electrical generator which is exposed to the wind at an elevated location on a boat.
It is another object of the present invention to obtain the foregoing objects and also provide for an improved wind-impelled electrical generator assembly that is self speed regulating, that is maximally exposed in low or null wind speeds, yet substantially unaffected by periods of high winds and which is sufficiently durable to withstand exposure to the elements.